Melobasis dissimilis, Levey, 2018

Levey, Brian, 2018, A revision of the Australian species of the genus Melobasis Laporte & Gory 1837 (Coleoptera: Buprestidae), Part 2 (Revision of the nervosa species group), Zootaxa 4528 (1), pp. 1-79 : 23-25

M. dissimilis sp. n.

(Figs 30–31, 86–87, 137–138, 170, 180, 193)

Type locality: Geraldton , Western Australia .

Type specimens examined. Holotype ♂ ( SAMA) Geraldton / HOLOTYPE Melobasis dissimilis sp. n. B. Levey 2012. Paratypes as follows [all bearing label PARATYPE Melobasis dissimilis sp. n. B. Levey 2012]: Western Australia : 2♂, 2♀ ( BMNH, MVMA) S.W. Australia, Yallingup, Nov.1913, R.E. Turner, 1914-190 ; 2♂, 1♀ ( BMNH) data as above but 1–12 Dec. 1913 [♀ labelled as Melobasis occidentalis Carter Type ♀] ; 4♂ ( ANIC, BMNH) Nov. Holl. Occid. / De Boulay / Fry Coll. 1905-100 ; 1♂ ( BMNH) W. Australia 69.64 ; 1♀ ( BMNH) W. Australia: Dongarra, 11–28.x.1935 / AUSTRALIA: R.E. Turner, B.M. 1935-240 ; 7♀ ( SAMA, WADA) Geraldton & Mullewa, Lea ; 2♀ ( ANIC) Geraldton, A.M. Lea ; 1♀ ( SAMA) W. Australia ; 1♀ F.H. Uther Baker, Geraldton, W.A. 27.9.56; 1♂, 1♀ ( NMWC) W. AUSTRALIA: Coronation Beach, 25 km N. of Geraldton, 28?33′5″ 114?33′53″. 22.ix.2012. Flowering Acacia . B. Levey. NMW.Z. 2012.071 ; 1♀ ( CLBC) Australia: WA, Coronation Beach, 20 km N. Geraldton, 7–8.ix.1981, H. & A. Howden .

Other specimens examined. Western Australia: 2♂ (MPC) False Entrance, Sep. 12 1981, Acacia lvs. M. Golding; 2♂, 2♀ (MPC, TMSHC) Shark Bay, 19.9.1989, G. Harold; 2♂, 3♀ (TMSHC) Coronation Beach, 1 Sep. 2006, Acacia saligna leaves; as above but 21 Oct. 2007, Acacia in dune; 2♀ (MPC) as above but 31 Aug. 2007, Acacia leaves, D. Knowles ; 1♀ (MPC) 10 km S. of Useless Loop, Aug. 23 1979, Acacia lvs., D. Knowles; 1♀ (MPC) 45 km E. of Geraldton, 11 Jan. 1992, on Allocasuarina, M. Powell & M. Golding.

Diagnosis. General diagnosis: length 6.7–9.4 mm; sexually dichromatic: ♂ entirely golden green to emerald green; ♀ entirely olive green, brownish bronze or blackish bronze; underside laterally sparsely clothed with silvery pubescence, most of prosternum, prosternal process, mesosternum, and central parts of metaventrite and abdominal ventrites glabrous or sparsely pubescent.

Head (Fig. 170): very densely punctate with small round strong punctures in ♂, slightly less densely punctate in ♀, the punctures weaker; moderately densely clothed with moderately long silvery pubescence which does not obscure the punctation; rims of the punctures microreticulate in ♂, shiny in ♀; clypeal excision very shallowly excised, with a narrow poorly defined impunctate, shiny or microreticulate border; clypeal peaks right angled, without, or with a slightly defined clypeal angle; vertex flat, half width of head across eyes when viewed from above; eyes very strongly convex in ♂, slightly, to much less convex in ♀.

Antenna (Fig. 193): not sexually dimorphic; segments 3 or 4 slightly triangularly expanded, sometimes 3 almost subcylindrical, segments 4 or 5–11 with expansion almost quadrate.

Pronotum: 1.50–1.81 × as wide at base as long in midline; anterior margin strongly bisinuate, with a moderately well developed, broad median lobe; with a narrow but well defined beaded margin; posterior margin very weakly bisinuate; widest at basal third or mid-length; lateral margins parallel sided for a short distance from basal angles before diverging to widest point, or rectilinearly weakly diverging from basal angles to widest point, before converging to apical angles; basal angles acute; as wide as or very slightly narrower at base than elytra at base; lateral carina almost straight about three-quarters complete; punctation in central fifth sparse, mostly consisting of small transversely ovate punctures, sometimes with traces of an impunctate median line, becoming more dense, and transversely elliptical lateral to central-fifth, before becoming larger, mostly round and dense, to very dense in lateral half; with inconspicuous, very sparse, short, silvery pubescence, close to the anterior angle.

Scutellum: shield shaped, about one-sixteenth to one-fourteenth width of elytra at base.

Elytra 2.21–2.47 × as long as wide at base; basal margin very weakly bisinuate; slightly widening from the base over the humeral callosities thence parallel sided or slightly widening to mid-length, before narrowing to the sub-acute apices; lateral margins in apical half and apices, with moderately coarse acute serrations; sutural margins slightly raised in apical two-thirds to three-quarters; each elytron usually with traces of three approximately equidistant costae; sometimes only 1 st costa well defined extending almost from base to apex; 2 nd and 3 rd costa of variable development, sometimes scarcely visible; subsutural depression sparsely punctate with pin-prick punctures; punctures between the 1 st and 2 nd costae slightly larger, mostly arranged in regular longitudinal series adjacent to the costae; punctures lateral to the 3 rd costa becoming dense, larger, transversely oval to elliptical; weakly microreticulate.

Hypomeron: contiguously punctate, with moderately large, very shallow, mostly ovate punctures, with sparse moderately long silvery pubescence.

Prosternum: with a well defined bead at the anterior margin; the anterior margin at the same level as the area behind; prosternal process slightly widening distally, sparsely punctate, with small round and pin-prick punctures, glabrous or with very sparse scattered short silvery pubescence.

Mesanepisternum (Fig. 180): shiny, sparsely to densely punctate, with large, very shallow, round and ovate setae bearing punctures in the anterior half, microreticulate, and with smaller variably shaped punctures in posterior half.

Central part of metaventrite, inner part of metacoxa, central part of abdominal ventrites glabrous or sparsely pubescent, more sparsely and weakly punctate than lateral parts of these structures, which are very densely punctate with round or lunate punctures, with sparse moderately long silvery pubescence.

Apical ventrite (Figs 137–138): lunate punctures not coalescing near the lateral margin, not forming grooves; excision in ♂ broad, W shaped, with a narrow oblong to subtriangular truncated flange at the centre, with long slightly inturned lateral spines (Fig. 137); ♀ narrower, U-shaped, without a visible flange, the lateral spines long, very slightly inturned (Fig. 138)

Fore tibia: ♂ strongly curved, with a very small triangular tooth at apex and a slightly developed setal brush on the anterior face at the apex; ♀ tibia weakly curved, tooth absent.

Mid tibia: ♂ strongly curved with an elongate depression along the ventral face; ♀ very weakly curved, without a depression.

Aedeagus (Figs 86–87): parameres gradually constricted before the apical setae bearing part; apical setae bearing parts scarcely widened, about one third the total length of the parameres, with numerous, very small, inconspicuous, spine-like setae, in addition to the usual long fine setae; median lobe truncate at the tip.

Ovipositor: not examined.

Comments. This species is most likely to be mistaken for M. costipennis in having similar colour dichromatism. It differs in the form of the aedeagus in which the parameres are gradually constricted before the apical setae bearing part and the very small inconspicuous spine-like setae (strongly constricted and with large obvious spine-like setae in M. costipennis ), and also in having the punctures between the 1 st and 2 nd costae being mostly arranged in regular longitudinal series adjacent to the costae (punctures in this area not obviously arranged in longitudinal series in M. costipennis ) It is also smaller, but there is a slight overlap in size (length 6.7–9.4 mm in M. dissimilis , 9.2–12.2 mm in M. costipennis . In the field it is also likely to be mistaken for the distantly related M. occidentalis Carter 1923 (obscurella species group), which is of a similar size and colour.

Etymology. This species is named for its strong sexual dichromatism.

Bionomics. Adults have been collected from August to January, with most records in September. Adults mostly collected from Acacia spp. leaves (including Acacia saligna ) in coastal areas, with a single record from Allocasuarina sp. inland. Larval host unknown.